Thanks for your interest in this Science Buddies project. On the project webpage, you should see a list of tabs across the top. The second tab, "Background," has some good information on the scientific concepts of standing waves. The Background section also provides several references, including:
Henderson, T. (n.d.). Sound Waves and Music. The Physics Classroom. Retrieved December 11, 2014.
Nave, C.R. (n.d.). Standing Waves on a String. HyperPhysics, Department of Physics and Astronomy, Georgia State University. Retrieved July 5, 2007.
Nave, C.R. (n.d.). Air Column Resonance. HyperPhysics, Department of Physics and Astronomy, Georgia State University. Retrieved July 5, 2007.
The Henderson reference, specifically, has a nice section on the speed of sound (
https://www.physicsclassroom.com/class/ ... d-of-Sound). On this page, you will find an embedded link to material discussing the speed of a wave (
https://www.physicsclassroom.com/Class/waves/u10l2d.cfm).
Good luck!
Dr. Christina Payne